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2. Proudfoot, C.G.: ‘Industrial implementation of on-line computer control of pH’, 1983, DPhil thesis, University of Oxford
3. Gustafsson, T.K.: ‘A study of modelling and control of pH’, 1984, Doctoral thesis, Abo Akademi Report 84-4
4. Shinskey, F.G.: pH and pION control, (Wiley 1973)
5. Moore, R.L.: Neutralisation of waste water by pH control, (Instrument Society of America 1978)